1. Field of the Invention
This invention relates to treatment of tissue, particularly in the sphincters and other muscles of the digestive, circulatory, respiratory, urinary and reproductive systems. Such treatment can be performed using ablation, coating, expansion, plumping, shaping, shrinking, or related techniques.
2. Related Art
The circulatory, respiratory, urinary, reproductive and digestive systems of human beings, livestock and other mammals are subject to a number of disorders and diseases. Disorders in the circulatory system include aneurysms of the aortic arch, thoracic aorta and abdominal aorta. Disorders in the respiratory system include occlusion of the trachea and tumors and polyps in the hypopharynx, oropharynx, nasopharnyx and larynx. Disorders in the urinary system include incontinence and urinary neuropathy. Disorders of the reproductive system include obstruction of the vas deferens, obstruction of the fallopian tubes, uterine cysts and fibroids, prolapsed uterus, menorrhagia and tumors or cancerous tissue. Disorders in the digestive system include Barrett""s esophagus, occlusion of the bile ducts, occlusion of the pancreatic ducts, tumors and cancerous tissue found in the stomach and related structures. Other disorders in the rectum and colon include hemorrhoids (external and internal), fecal incontinence, prolapsed rectal muscles, rectal muscle spasms, anal fissures, polyps, diverticulosus, diverticulitus and pilonital cysts.
Known methods for the treatment of these disorders include surgery, pharmaceutical remedies, chemotherapeutic regimens, radiation, photodynamic therapy and lifestyle modification. These methods only occasionally achieve the goal of successful treatment of known disorders. One problem in the known art is that these methods suffer from several drawbacks.
Drawbacks to surgical treatment include its highly invasive nature, associated risks, possible iatrogenic effects, and high cost. Drawbacks to pharmaceutical and chemotherapeutic treatments include their relative ineffectiveness (particularly in the oral cavity and adjacent respiratory structures) and associated side effects. Moreover, these approaches are contraindicated for many patients. Drawbacks to lifestyle modification include relatively poor patient compliance and relative ineffectiveness. Drawbacks to photodynamic therapy include its frequent unavailability and limited applicability. Drawbacks to radiation include side effects such as exhaustion, radiation burns, chronic dry mouth and permanent distortion of the taste buds. Accordingly, it would be advantageous to provide techniques for treatment of these disorders that are not subject to these known drawbacks.
The use of radio frequency (RF) to ablate tissue in the body (such as heart muscle tissue) is known in the art of cardiac treatment. However, known systems using RF energy are still subject to several drawbacks. One known problem in the art involves the creating a controlled pattern of ablation throughout the interior of an organ. For instance, it is sometimes desirable to apply RF energy to the entire interior of a body cavity such as a urinary bladder. While known systems allow RF energy to be applied to one part of a body cavity, followed by another part, they do not permit the RF energy to be simultaneously directed to the entire interior of a body organ.
A second problem in the known art of applying RF energy involves minimizing thermal damage to adjacent body tissues. Frequently, application of RF energy to targeted tissue results in collateral thermal damage to adjacent tissue because it is difficult to control the temperature of the adjacent structure.
A third problem in the known art is that it can be difficult to block the flow of bodily fluids and gases into an area of the body where tissue ablation is taking place. Bodily fluids can dissipate and detrimentally absorb the energy to be applied to the tissue to be ablated. Dissipation of bodily fluids detracts from the goal of successful tissue ablation and etching.
A fourth problem in the known art involves directing and positioning the electrodes in the body cavity or orifice. Difficulties in accurately positioning the electrodes in the target orifice detract from treatment. Frequently, unhealthy tissue can remain unablated while healthy tissue is removed. Difficulties in directing and positioning the electrodes are particularly problematic because one of the goals of treatment is to minimize collateral damage to healthy tissue and to completely ablate diseased tissue.
A fifth problem in the known art involves difficulty in the simultaneous use of complimentary technology. Known systems do not provide for optimal, simultaneous use of auxiliary tools for visualization, feedback technology and drug administration.
Accordingly, it would be advantageous to provide improved techniques for treatment of disorders in the bladder, esophagus, uterus, fallopian tubes and vas deferens, sinus cavities, aorta, larynx, pharynx and the sphincters and muscle tissue associated with these organs in humans, livestock and other mammals. For example, it would be advantageous to provide devices bearing different arrays of electrodes embedded in an inflatable microporous balloon. Such devices can be coupled to apparatus for drug administration and tissue visualization and mounted on a catheter that can be either manually or laproscopically inserted into a body orifice or organ. Such devices would allow medical or veterinary personnel to (1) provide for the controlled, such as uniform, application of energy throughout the interior of a body cavity, (2) visualize the tissue to be ablated or etched, (2) monitor and regulate the temperature of adjacent tissue, (3) seal off the area from fluids and gases that would disturb the area to be ablated, (4) ablate or otherwise treat diseased tissue while sparing healthy tissue and (5) provide for the localized administration of drugs to numb the area and treat the disorder. These advantages are achieved in an embodiment of the invention in which medical or veterinary personnel use a catheter that supports a multiple array of regularly spaced electrodes embedded in a balloon-like microporous sacs that can be inflated with saline or air. Temperature regulation is achieved by partially infusing the balloon with a circulating fluid whose temperature can be maintained so as to cool the surface of the balloon. Multiple controls for operation of individual electrodes, visualization and drug administration are mounted into the catheter, along with sensors that measure temperature, impedance and other properties.
The invention provides a method and system for treatment of body structures or tissue. The particular treatment can include one or more of, or some combination of ablation, coating, expansion, plumping, shaping, shrinking, or related techniques. The particular body structures or tissue can include one or more of, or some combination of regions, including the rectum, colon, esophagus, vagina, penis, larynx, pharynx, vas deferens, uterus, trachea, large intestine, small intestine, sinus, bladder, auditory canal, aortic arch, abdominal aorta, thoracic aorta and all associated sphincters as well as smooth and striated muscles.
In a first aspect of the invention, positive pressure is used to inflate a balloon having a microporous membrane with a flowable substance, such as air or saline. Inflation of the balloon inside a targeted organ causes a set of electrodes, either embedded in or otherwise positioned with regard to, the microporous balloon to come into contact with either a portion of, or the entire interior of, the targeted organ. Negative pressure can deflate the balloon and allow the catheter to be removed from the body without damaging adjacent body structures.
In a second aspect of the invention, the electrodes are coupled to sensors that measure sympathetic and parasympathetic nervous activity in selected areas of the targeted region. These measurements are useful both in making diagnostic assessments as well as in determining treatment parameters.
In a third aspect of the invention, the electrodes are coupled to sensors that measure properties of the target region such as temperature and impedance. Measurement of these properties permits the use of feedback technique to control delivery of the RF energy and administration of fluids for cooling and hydrating the affected tissues.
In a fourth aspect of the invention, an environment proximate to or surrounding the targeted treatment region can be isolated or controlled by blocking the flow of gases or liquids using an inflatable balloon or other device positioned proximate to the tissue that is to be ablated. The inflatable balloon can also serve to anchor the catheter in place and prevent the catheter from being expelled from the body. The inflatable balloon can also insure that locally administered drugs remain in the area where most effective or needed.
In a fifth aspect of the invention, the catheter includes an optical path that can be coupled to external viewing apparatus. The position of the electrodes in the body can therefore be determined by fluoroscopic, fiber optic, or radioscopic techniques.